Liquid fuel burner



L. A; cocKLlN LIQUID FUEL BURNER April s, `1932 l Filed Nov. 29.

ATTORNEY lli Patented Apr. 5, 1932 PATENT FFIC LEWIS A. COCKLIN, OF G'RISW'OI'JID,` IOWA.

LIQUID FUEL BURNER Application filed November 29, 1929.

My invention relates to burners for oil or other liquid fuel, and it is the general object thereof to provide simple and eflicient means for burning the heavier and lower grades of petroleum products, which when vaporized leave considerable quantities of non-volatile or carbonaceous residues. More particular objects of my invention are to provide oil burning means applicable to furnaces and heating plants of all kinds, and adapted for installation in furnaces originally equipped for burningl coal or other solid fuel; and to pr-ovide oil burning means operable alternatively under forced or natura] draft, and capable of a wide range of variation in the volume of fuel consumed during a lgiven period of operation, whereby in a burner of sufficient capacity to heat a furnace during' extremely cold weather, the supply of fuel may be proportionally reduced during milder weather, according to the amount of heat actually required, without resorting to intermittent operation of the burner to avoid excessive heating of the furnace, and thus necessitating the use of pilot-lights or other special means for re-igniting the burner when operation thereof is resumed.

A further object of my invention is to provide an oil burner in which the oil and the air for supporting combustion are delivered jointly upon the surface of a body of refractoryporousmaterial of lowheat conductivity, which in the normal operation of the burner becomes incandescent and serves to instantly vaporize the oil as the latter comes into contact therewith.

A further object is to provide a burner of the type above mentioned, wherein the air supplied to the burner is preheated, and the oil is liept coolto prevent vaporization thereof prematurely, and deposit of residues in the fuel supply pipe.

A further object is to provide in a burner of this classmeans for carrying off the surplus or excess of fuel in the case of an over-supply, or should the burner be accidentally extinguished while the oil is being' supplied thereto, or should an excess of fuel be supplied when starting the operation of the burner.

A further object of my invention is to pro- Serial No. 410,469.

vide an oil burner of the gravity type, wherein the fuel is delivered to a retort filled with porous refractory material and burns at the surface of the refractory filler, but in which there is no accul'nulation of the liquid fuel within the retort under normal operating conditions, and the retort and its refractory filler remain substantially dry except when starting the operation of the burner or when the operating conditions are abnormal.

A further object of my invention is to provide an oil burner for furnaces and the like, adapted to produce a luminous flame, and providing` within the combustion chamber of the furnace a body of refractory material which ismaintained at incandescence during normal operation of the burner, so that the walls of the combustion chamber will be heated not only convectively by the combustion products but also by the direct radiant heat emitted from the luminous flame and from the incandescent body or refractory material.

A structure embodying my invention is shown in the accompanying` drawings, wherein Fig. 1 is a plan view of the retort, the air-flue and the cap for the overflow pocket being in section on the lines 1 1 of Figs. `2 and 3, Fig. 2 is a vertical longitudinal section on the line 22 of Fig. 1, Fig'. 3 is a det-ail vertical section on the line 3*-3 of Fig. 1, and F lv is a diag animatie vertical section of a furnace having the burner mstalled therein. Y

In carryingl out my invention according to the illustra-ted embodiment thereof, I provide an open-topped retort having a vertical cylindrical wall 10, beveled slightly inward at the lower portion 11. where the wall 'joins the closed bottom 12. At one side the retortwall has a concave or re-entrant portion 13 which is continued outwardly to form a vertical aunular socket 14 for receiving` removably the lower portion of the air-flue 15. The upper portion of said air-flue is an inverted U-shaped tube 16 having an open end terminating centrallyabove the retort and spaced from the upper edge thereof. rlhe open end of the flue may be slightly contracted at the delivery orifice 17 for increasing `the vesurrounded by the wall 1() there is disposed locity of the air delivered to the retort, when the burner is to be operated under low-draft conditions, such that increased velocity of the air-stream at the delivery orifice becomes desirable. A flange 18 formed integrally with the flue 15 rests normally upon the upper edge of the socket 14, and beneath said flange is a rectangular lug 19 which fits iin a 'notch in the upper edge of the socket, to prevent turning of the flue within the socket and displacement of the delivery and thereof from its central position above the retort. At the sides of the retort-wall and on the socket 14 are lugs l2O bored vertically to receive the adjustable legs 21 which are secured in the lugs by set-screws 22, as shown, and serve to support the retort at the desired height.

In the arrangementof the burner shown in Fig. 4, the retort is disposed centrally in the lower portion of the combustion chamber 23 of the furnace, and air is supplied to the flue 15 through a horizontal conduit 24 extended through the lower door-opening of the furnace-body, said opening being closed about said conduit by means of brick 25 or other suitable means which may be cemented to substantially seal lthe opening and prevent the admission of air to the combustion chamber except through the conduit and the flue 15 with which the inner end of the conduit is connected. The air supplied through the conduit 24 may be impelled by natural draft, or a suitable blower 26 may be connected with the external end of the conduit, as shown, to provide forced draft, and when the blower is provided, operation thereof may be discontinued at times, and air drawn through an opening in the blower-casing by natural draft only. i

`Within the open-topped retort-chamber a mineral wick or filler 27, comprisin(r irregular fragments of porous refractory material of low heat conductivity, said wick or filler preferably being of the composition disclosed in Letters PatentA No. 1,738,138, is-V sued to me December 3, 1929. y

' The oil or liquid fuel is delivered uponthe upper surface of the mineral wick or filler 27, centrally thereof and concentric with the current of air from the delivery orifice 17 of the air-flue, the oil being supplied through a nozzle-member 28, arranged within the upper portion 16 of the air-flue, and having its discharge-opening above and concentric with the air-delivery orifice. At the upper end of the member 28 is a plug 29 which extends vertically through a tubular boss 30 on the flue, to thereby aline the nozzle-member with `the air-delivery orifice. The oil supply pipe has a. curved terminal portion of elbow 31 connected with a side-opening in the nozzle-member 28, said elbow being arranged centrally of the'curved upper portion 55 16 of the air-flue, and there being a coupling Vto a point outside the furnace.

32 connecting the elbow with a vertical pipe 33 extending down centrally through the ascending leg of the flue. At the lower end of the pipe 33 a short elbow 34 connects the same with a pipe 35 extending horizontally through the conduit 24 to a point outside the furnace, thence laterally through the side of said conduit to a-control-valve 36, to which the fuel is supplied through a pipe 37 from a suit-able source.

f, t one side of the retort, adjoining the socket 14, the retort-wall is extended to form a pocket 38which is separated from the retort chamber by a. cross-wall or baille 39 0f which the upper edge is below the top of the sidewall 10. Fitting removably over the top of said pocket 38 is a cover or cap 40 having lugs 41 which extend down into the pocket to retain the cap in place over the same. At the inner edge of the cap is a depending lip or flange 42, arranged flush with the inside of the retort-wall 10 and extending to a level below the top of the baffle 39 and in spaced relation thereto, as shown in F'ig. 3. The arrangement is such that should oil accumulate in the retort, in the interstices of the filler 27, to the level of the top of the baffle 39, it will then overflow said baffle into the pocket 38, whence it may drain ofl" through an overflowfpipe 43 connected with the bottom of the pocket and extended therefrom The overflow of oil through the pipe 43 may be caused to operate safety devices `for reducing or stopping the supply of fuel to the burner, in any of the various ways common and well-known in the art. i

For starting operation of the described burner, the liquid fuel is first supplied at a slow rate, such that a very small stream of the liquid will emerge from the nozzlemember 28, without pressure thereon, and descend by gravity to the surface of the retort-filler 27, passing centrally through the air-delivery orifices 17. W'ith fuel of moderate inflammability, the same may be ignited by merely applying a match to the descending stream. With extremely heavy and non-v volatile oil, ignition may be effected by placing a small amount of any easily inflammable material upon the surface of the filler 27 and igniting said material prior to or simultaneously with the starting of the flow of oil.`

Upon the ignition of the liquid fuel, the flame produced thereby is spread outwardly across the surface of the filler 27 by the impinging current of air from the orifice 17, and because. of the low heat-conductivityv of the filler material the upper portions thereof are quickly raised to a tempera-ture of incandescence, so that thereafter as it comes into Contact with the filler the oil will be immediately vaporized and combined with the incoming air to pro* duce a continuous flame of which the volume and intensity will be proportional to the rate at which the fuel is supplied. While starting the operation, and before the surface of the filler has been heated sufficiently to cause immediate and complete vaporization of the fuel, some portions thereof may descend through the filler and accumulate in the lower portion of the retort. As the heating of the filler proceeds, however, and after the surface has attained the required vaporizing temperature, the liquid from the lower portion of the retort will be returned toward the surface by capillary action of the porous material, being thus brought into the highly heated upper stratum of said material, there i to be vaporized and burned together with the freshly incoming supply of fuel. Thus in the normal operation of the burner there is substantially no liquid fuel in the retort, and the apparatus may be properly designated as a clry1etort burner for liquid fuel.

It will be noted that by reason of the radial spreading of the flame outwardly from the central portion of the filler surface, where the oil falls thereon, and about which the airecurrent from the orifice 17 impinges, the flame at one side of the retort will strike and heat the ascending leg of the air-flue, so that the incoming air will be preheated. By rea* son of the inclosing of the fuel-supply pipe within the air-flue, however, said pipe and the nozzle-member 28 will be kept relatively cool by the air passing through said flue, so that preheating and premature vaporization of the oil will be prevented, and no opportunity afforded for the formation of carbonaceons residues within the fuel-pipe or its nozzle-member, to clog or obstruct the same. Likewise, because the vaporization of the fuel occurs exclusively in the upper stratum of the filler, and principally upon the surface thereof, any non-volatile or carbonaceous residues will be burned away simultaneously with the combustion of the volatile constituents. Also. any solid residues of the fuel, formed within the body of the filler by the vaporization of portions of the fuel which have descended thereinto during the starting operation hereinbefore described, or in any manner, will be confined to the upper stra tuin of the filler, which constitutes the vaporizing zone for such portions of the fuel; and during;` continued normal operation of the burner said upper stratum of the filler becomes sufficiently heated, and sufficient air will )ass thcreinto through the interstices between the granular fragments, to cause burning away of the residues after a short period of normal operation. It will thus be seen that liquid fuel of any density may be burned, without liability of accumulation of carbonaceous residues to clog, obstruct, or interfere in any way with continued operation of the burner; and that any temporary deposit of non-volatile but combustible material will be automatically burned out durwith `greater efficiency than would be possible by the mere convective transfer of heatthereto by the combustion products.

At very low rates of fuel supplyithe com` bu'stion will occur over a restricted area of the filler surface immediately ad] oimng the pointr at which the fuel falls thereon, and in the zone of combustion the filler will be maintained at a suicient temperatureto vaporize the fuel, because the low conductivity of the filler material will inhibit conduction to the remoter portions of the filler the limited amount of heat imparted thereto by the small flame. Thus, by the use of the granular refractory porous filler having low heat conductivity and the delivery of the liquid fuel upon a limited area of the surface of said filler, there is attained a wide variability in the amount of fuel which may be burned during a given period of operation, and the heat production is thus controllable to .secure any desired variation thereof without resorting to intermittent operation of the burner.

Now, having described my invention, what I claim and desire to secure by Letters Patent is:

l. In a liquid fuel burner, a relatively deep retort open at the top thereof, a body of porous granular refractory material of low heat conductivity substantially filling said retort and having a substantially level upper surface, an air-flue having a delivery orifice positioned centrally above said upper surface of the refractory material and directing a column of air downwardly to impinge thereon, a fuel-pipe inclosed by said air-flue and having a discharge opening positioned adj acent to the delivery orifice thereof and ar ranged to discharge liquid fuel within said column of air to descend by gravity onto the surface of the refractory material while inclosed by said column of air, and means for draining excess liquid fuel from the retort to a level below the surface of the refractory material therein, whereby the upper layer of said refractory material remains substantially unwetted by the fuel and at an incandescent temperature during operation of the burner.

2. In a liquid fuel burner, the combination with a relatively deep retort open at the top thereof, a body of porous granular refractory material of lowl heatconductivity filling said 1,., iam.)

retort and having a substantially level upper surface, and means for draining liquid from the retort to a level below said upper surface of the refractory material, whereby the upper layer of said material remains substantially dry and unwetted except by liquid rising by capillary action from the lower portions of the material; of an air-flue having a delivery orifice positioned centrally above the upper surface of the refractory material to direct a column of air downwardly to impinge on said refractory material, and a fuelpipe inclosed by andspaced from the walls of said air-flue having a discharge opening positioned adjacent to said delivery orifice to discharge liquid fuel within the column of air to descend by gravity onto the surface of the refractory material while surrounded by said column of air.

LEWIS A. COCKLIN. 

